Ben Affleck and Jennifer Garner Celebrate His Birthday Together

12/27/2016 01:45 pm EST

Jennifer Garner and Ben Affleck came together once again to celebrate the actor's 44th birthday at the Yellowstone Club in Montana on August 15 with their children Violet, 10, Seraphina, 7 and Samuel, 4, Us Weekly reports.

"There was a cake and they did the usual stuff: hiking and playing outside," an Affleck source shared. "They wanted to be together as a family."

Since announcing their divorce in 2015, Garner and Affleck have been adamant about maintaining a friendly relationship for their children's sake, and they have continued to do exactly that with family vacations, trips to Affleck's film sets and this most recent celebration as a family.

The source adds that the Yellowstone Club is one of the pair's "favorite places," as they previously spent Christmas at the resort last year and visited again in February with Tom Brady and Gisele Bundchen.

Garner and Affleck reportedly "got along great" during the week they spent in Montana, but the source was quick to add this does not mean they are getting back together. "They didn't sleep in the same room," the insider said. "And they are not getting back together."

"Ben is happiest when he's spending time with his family," another source told PEOPLE. "It was a great birthday."

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